Appendix C Technical data for the 7951
Page C.2
C.3 External connections You can make the following types of external connections to the 7951:
•INPUTS Analog Inputs from devices which monitor continuously
changing parameters and transmit analog signals.
These include:
• PRTs (PT100)
• temperature transducers (0/4-20mA)
• pressure transducers (0/4-20mA)
• differential pressure transducers (0/4-20mA)
• Viscosity transducers (e.g. Covimat 0/4-20mA)
• Calorimeters (0/4-20mA).
Pulse Inputs from devices which transmit information as
pulses. For example, a turbine (or positive
displacement) flowmeter.
Time period
(Dens./Visc.)
Inputs from devices where the frequency of the
transmitted signal is related to the parameter being
measured. These include:
• Density transducers (e.g. 7835 or 7826)
• Base density transducers
• Viscosity transducers (e.g. 7827).
Status One of two levels, to show the state of some part of the
system, such as whether a valve is open or closed.
•OUTPUTS Analog Outputs from the signal converter to those devices
(such as chart recorders) which require analog outputs
(0/4-20mA).
Pulse For equipment such as pulse summators or electro-
mechanical totalizers (open collector).
Status Outputs to equipment whose status is to be changed
as, for example, an output which opens or closes a
valve (open drain).
•SERIAL
COMMUNICATIONS
For receiving and sending information to other devices
linked to 7951. These include:
• Printers.
• Host computers.
• Master or slave 7951s, Chromatographs, etc.