OT: Honeywell UDC3300

One of our customers has a Honeywell UDC3300 with 2 current outputs. It has worked well for years controlling 2 Fisher valves to maintain water level in a storage tank. One of the valves is fed from city water and the other is fed from well water. They asked me to program one of the outputs from the UDC to go to 20mA whenever the digital input is on. In other words, they want the valve to go fully open or fully closed and no longer modulate. I have the manual but have not been able to figure this out. Thanks for your help.

Assuming this a UDC 3300E (E = expanded/enhanced model) that does 2 PID loops in one model, with a model number like:

DC330E - Kx - 2 D/E/G/H 3 - xx - xxxxxx - x
- 2nd character in 3rd field can be any of the alpha characters, any of which indicates 2 loops of control
- if the 3rd character is 0, then you need to purchase a digital input card (I suspect parts are still available)
- if the 3rd character is 3, then a digital input card was factory installed




I've never done this action on a two loop controller before, only on a single looper. So, whether the DI actions are unit-based or loop-based is conditional on how the factory made it, and the manual isn't exactly clear on the point.

There are two digital inputs (on the DI option card), each is assigned to a respective loop, when the controller is in 2 LOOP mode:

(UDC 3300E manual, pg 54, pdf)
DIG IN 1 Digital Input 1 Selections
NOTE: DIG IN 1 applies to Loop 1 when 2 LOOPS or CASCAD is configured.
DIG IN 2 Digital 2 Input Selections
Same as DIG IN 1
NOTE: DIG IN 2 applies to Loop 2 when 2 LOOPS or CASCAD is configured.

A digital input state change (when DI input is shorted by a dry contact closure) can force a full scale output value through one of two techniques, when the digital input's action is configured to either:

MAN FS
Unit goes to manual mode, output goes to the failsafe value.
Failsafe value has to be configured for = whatever value (%) which = 20mA on the output. (o or 100; depends on action, direct or reverse)

or

ToAout
Output is forced to value set at control prompt “AUTO OUT” when controller is in automatic mode.

A potential problem with setting Auto Out to a value = 20mA is that that's what the output will immediately go to on a cold start power up. So make sure that a 'cold start' can tolerate a 20mA output condition. The PID calculation immediately affects the output value, but 20mA might not be a reasonable cold start condition and slow responding PID terms might not be what is needed on a cold start.

I suspect that both MAN FS and ToAout are both loop actions (affecting only the loop the DI is associated with) but I can't guarantee it. MAN FS could well have been interpreted as a unit action, affecting both loops, or just a loop action for the specific loop that the DI is tied to. (I don't have a dual loop unit to play with to find out).

The manual is about a 600Kb file, so it won't post here (300Kb limit). Private message me with your email if you need a copy.

Dan

Dan,

Thanks for the reply. The UDC Model is a DC330E-KE-2D3(etc) which is the expanded model. We currently have the controller set up so if DIG 1 is on then Loop 1 is active and if DIG 2 is on then Loop 2 is active. Looks like our best solution is the first one you mentioned. We are wanting to do Loop 2. On page 61 of the manual I have there are settings for FAILMODE, which is Failsafe Mode and FAILSAFE which is the failsafe output value. Looks like we would need to change FAILMODE from NO LAT to LATCH and then set FAILSAFE to 100%. We would then set DIG 2 for MAN FS. Hopefully when DIG 2 input is off Loop 2 will go back to 0%. Seems to me this is the way it would work.

Randy

Hi Randy,

Just an idea... but have you tried changing the PI&D to just tune it that way?

I had one that I needed to do the same thing for a while back and I just brought the 'P' to 0 and I think the 'I' to a very high number... it was a cheaper way then replacing the controllers.

The new controllers have a pass through that you can set up... I did this last week to one while I was working on it, I made it when anything other then 4mA it would open 100%

Randy,
I'm mystified. What do you set the DI action to in order to enable/disable the respective loop?

The list of DI actions from the 3300E manual is posted below. I'd like to know what your DI's are set to.

I don't think you want the MAN FS to latch, assuming you can hold the DI closed for the duration needed. Otherwise won't someone have to come and manually unlatch the loop (RUN/HOld key?)

There are, in fact, 4 PID sets, two for each loop, so letting the reset action windup to 100% will work, too, using the DI's ToPID 2 action with a fast I setting like 0.01 min or 100 RPM

pg 77 (pdf):
PID sets 1 and 2 (TUNING) are for Loop 1 and single loop applications.
PID sets 3 and 4 (TUNING 2) are for Loop 2 in two-loop and cascade control applications.

DI action settings:

TO MAN MAN blinks Puts the controller into manual mode.
TO LSP Puts the controller into local setpoint 1.
TO 2SP RSP annunciator blinks; Puts the controller into local setpoint 2.
TO 3SP RSP annunciator blinks; Puts the controller into local setpoint 3.
TO DIR Selects direct controller action.
ToHOLD H blinks Suspends setpoint program or setpoint ramp operation.
ToPID2 PIDSET 2 in lower display; Selects PID set 2.
PV 2IN II (II blinks) IN; Selects the PV to equal Input 2.
PV 3IN III (III blinks) IN; Selects the PV to equal Input 3.
RERUN Resets the Setpoint Program back to the beginning of the first segment in the program and leaves the program in the same Run Or Hold mode that it was in when the DI closed. Opening the DI has no further effect.
TO RUN R indicator blinks Starts a stopped SP Program.
ToBEGN Resets the Setpoint Program back to the beginning of the first segment in the program and places the program into the Hold mode.
STOP I Disables PID Integral (I) action.
MAN FS MAN blinks Unit goes to manual mode, output goes to the failsafe value.
ToLOCK LOCKED when a key is pressed Disables all keys.
ToAout Output is forced to value set at control prompt “AUTO OUT” when controller is in utomatic mode.
TIMER Timer clock ( ) and time appear in lower display. Starts timer (momentary). Reopening switch has no effect.
AM STA Causes switch to Auto Manual Station mode.
ToTUNE TUNE ON in lower display Starts the Accutune process.
SPinit Forces the SP to initialize at the current PV value.
TRACK1 O blinks Allows Output 1 to track Input 2.
TRACK2 O blinks Allows Output 2 to track Input 2.
ToOUT2 O blinks Allows Output 2 to override Input 1.
TO RSP RSP annunciator blinks Selects remote setpoint, if enabled.
D L1/2 Displays loop not being displayed at time of closure.
RST FB Allows Input 2 to override the internal reset value, providing external reset feedback.
ToPURG MAN blinks and output value shows in lower display. Forces loop to manual mode with the output values set to the Output High Limit configuration.
LoFIRE MAN blinks and output value shows in lower display Forces loop to manual mode with the output set to the Output Low Limit configuration.
MAN LT Forces loop to manual mode, latched. Opening DI has no effect on Mode. UDC remains in manual mode.
REStot Resets the accumulated totalizer value. Opening the switch has no effect.

danw said:

Randy,
I'm mystified. What do you set the DI action to in order to enable/disable the respective loop?.

Click to expand...

Well I was actually able to find my old configuration sheet for this unit. I haven't actually touched this controller in probably 3 or 4 years. I can see why you were mystified. So was I. The digital inputs are already both set for MAN FS. What we are actually doing is disabling the Loop when the DI is active. Failsafe is set to 0. So if we want only Loop 1 to operate then we activate DIG IN 2 and vice versa.

I don't think you want the MAN FS to latch, assuming you can hold the DI closed for the duration needed. Otherwise won't someone have to come and manually unlatch the loop (RUN/HOld key?)

Click to expand...

You are correct. It looks like all I need to do is change the FAILSAFE for CONTROL2 to 100% and leave the FAILMODE at NO LAT.