FAQs


Q:What are the power requirements?

All ZOC modules require + 15Vdc and -15 Vdc for operation. This
voltage does not need to be instrument grade. Sensor excitation
voltage is developed on board the module.

Q:How do the valves in Scanivalve Modules operate?

All ZOC22, 23, and 33 modules have four way valves for each
sensor. Application of a control pressure causes a bladder to
inflate or deflate in each valve to compress a tube, forming an air
tight seal. The valve logic is a “reverse” logic. That is, the mode
not wanted is pressurized.

Q:What are control pressures?

Control pressures are used to switch the valves in a module to
one of the standard operating modes: Zero, Operate, Calibrate, and
Isolate. Electronic signals are not required to switch these
valves.

Q:How do the control pressures operate the valves?

The different modes of operation are obtained by applying the
control pressures in a logical sequence. Truth Tables may be found
in the appropriate module hardware manual that show the logic
required for proper operation.

Q:Do control pressures have to be applied at all times?

All ZOC22, 23, and 33 modules require a control pressure to set
the mode of operation for the valves. The control pressure applied
should be 65 psi.

Q:What quality of air should be used for control pressures?

In order to prevent damage to the valves and sensors, the
control pressures for all modules must be “Instrument Grade”. For
more information, please refer to ISA Specification ISA-S7-3.

Q:I have lost my backup coefficients. What can I do?

Scanivalve Corp keeps a record of the coefficients for each
module generated in the most recent calibration performed at
Scanivalve Corp. These coefficients can be obtained at no charge by
contacting Scanivalve Corp, Product Support Dept.

Q:How do I address the modules?

Addressing is part of the DSM Series modules, so a user does not
need to interface to the address lines. If a module is not used
with a DSM series module, then the addressing would be a 4 to
6 bit address line depending on the number of sensors in the
module. All address line inputs are pulled up to the +15 Vdc
input.

Q:How often should I calibrate the module?

ZOC modules should be re-calibrated at a six month interval for
the best accuracy. Scanivalve Corp provides a utility program for
customers who can perform their own calibrations. This program is
called PressCal and may be downloaded from this website at no
charge.