I guess I should have included the specs on the input and output points for the HSCE2 (which appear to be different than the HSCE):
For the Z input in question:
Input voltage: 24 vdc (can also be 5vdc but I'm using 24)
Input Voltage Range: 10vdc to 30vdc
On-State Voltage (min): 10V
Off-State Voltage (max): 3V
Max Off-State Leakage: 100 microA
Input Current (max): 20 mA
Input Current (min): 6.3 mA
Nominal Input Impediance: 1500 ohms
Min Pulse Width: 475 nano-sec
Min Pahse Separation: 200 nano-sec
Max Input Freq: 1 MHz
Isolation from backplane: 1000 V
Isolation from Outputs: 500 V
For the high speed output in Question (which is listed as
sourcing
Output Voltage Range 5-30 Vdc
Max On-State Output Current: 1.0Amp @ 60 deg C.
Max ON-State Voltage Drop: 0.5V
Max Off-State Leakage current: 100 microA
Isolation from backplane: 1000 V
Isolation from Inputs: 500 V
One concern I have is that the max off-state leakage for both sides is the same. If both are at or near this limit of 100 uA am I in danger of seeing a false transition on the input?
You said you wanted to treat the Z input as a 'HOLD' command to the counter. On a cursory look through my manual, I didn't see where you could configure the module that way. The Z signal from an encoder is normally a marker signal that occurs once per revolution of the encoder. It is most frequently used in a homing routine to get an axis back to a known position. The 1746-HSCE manual describes how to configure the Z signal as a 'RESET' command.
For the HSCE2 the Z input can be programmed to perform one of several functions:
- No Preset - ignored
- Soft Preset Only (Internal bit used for marker function) Physical input ignored
- Store / Continue (Copies current count to register - flags SLC)
- Store / Hold / Continue (Same as above but Holds value when Z input high)
- Store / Preset / Hold / Resume - (Stores current count & flags slc, resets count to preset value and holds count until Z goes low again)
- Store / Preset / Start (Stores current count, flags slc, sets count to preset value and keeps counting)
This last option seems to mimic the traditional encoder Z channel functionality
Anyway, this is some more informaiton which seems to show that the HSCE and HSCE2 are definately different birds