Appendix C Technical data for the 7951
Page C.6
Input trigger level 0.5V RMS (1.2V p-p), Maximum 30V
Input impedance 10kΩ nominal
Digital (Status) Quantity 7951MAA****** (Klippon): 6 off
7951MAB****** (D-type): 10 off
Options Option for extra status inputs:
7951MAA****** (Klippon): 0 off
7951MAB*38*** (D-type): 8 off
Input voltage required 5 to 24V per channel (opto-isolated)
Update rate 0.5ms for prove detect, others 250ms maximum.
Special Notices Status Inputs 1 and 2 are fleeting contact ball detectors for
prover interface (opto-isolated). They can also be used as
normal status inputs.
Outputs
Analog Quantity 4
Options Option for extra 4-20mA analogue outputs:
7951MAA*38*** (Klippon): 4 off
7951MAB*38*** (Klippon): 4 off
Type of output Current (powered by 7951)
Power One 24V supply with capacity for 8 outputs @ 25mA each.
Maximum loop impedence 1KΩ
Type 0/4 to 20mA (selectable)
Zero offset 20% or 0% (keyboard selectable)
Span selection Unlimited (keyboard selectable)
Accuracy 12-bit (±0.075% of full scale)
Resolution 1 part in 3500
Output impedence 1MΩ minimum
Output representation Any measured ot computed value (keyboard selectable)
Update rate 0.1 seconds minimum
Isolation All analog outputs are galvanically isolated from ground
Long term drift <20ppm per 1000 hours for first 1000 hours,
subsequently far less
Special Notices 1. The maximum load impedance that the analog outputs
can drive is 1K Ohms. This must include any barrier
impedance and the load itself.
2. Analog outputs are “Active Loops”. (Active loops are
powered by the device providing the current output.
“Passive loops” are powered externally, usually by the
device receiving the current)