Section 4
ZGARD C 4-Channel Controller
General Information
OPERATING SPECIFICATIONS
Remote Sensor Inputs
Up to 4, 4-20mA analogue, 2 or 3wire
OR
RS485 digital data bus, 4-wire connection
Remote Sensor Power
24Vdc at 100mA / Input
Network Capacity
4 Remote Gas Sensors
Power Requirements
(Optional)
Standard 110Vac, 50/60 Hz ± 10% at 0.5 Amps
220Vac, 50/60 Hz ± 10% at 0.25 Amps; 24Vdc
±
10% at 1.0 Amps
Temperature
Operating: -10° to 40°C (14° to 104°F); Storage: -20° to 50°C (-4° to 122°F)
LED Readout
1 + 3 Digit LED display exhibits the channel number and gas level, at 2 second intervals
Status LED Indicators
Discrete Warning, Alarm and Sensor OK for each channel
Audible Alarm
Electronic device, 93 dB @ 0.3 meters
Pushbutton
Alarm reset and Silence function
Alarm & Warning Set points
Factory set at 35% and 50% Full-Scale, unless otherwise specified (Field Adjustable)
Sensor Fail Set point
Non-adjustable
Time Delays
Fixed 5 minutes ON delay for Alarm and 5 minutes OFF delay for Warning
or
manually
adjusted from 0 to10 minutes
Relay Outputs
4-Warning Relays and a common Alarm Relay and a Sensor Fail Relay: Form C - SPDT
Relay Action
Alarm Relay Latching or Non-Latching, jumper selected
Relay Contacts Rating
10 Amps 1/8 H.P., 125Vac, 5 Amps, 30Vdc, 6 Amps 1/8 H.P., 277Vac
(Optional) Signal Output
4-20mA, high select analogue output
Enclosure
(Optional)
Metal NEMA 1
Fiberglass NEMA 4X design
Dimensions
15” H (381 mm) x 12” W (305 mm) x 3.75” D (95 mm)
Weight
6.8kg (15 lbs.)
Certification
ENTELA (to CSA Standards)
Sensor Inputs:
The ZGARD C 4-Channel controller
accepts up to 4 remote gas sensors. The MSA ZGARD
S or GS, 4-20mA 2 or 3-wire analogue or RS485 type
sensors. The RS485 serial communication sensors are
automatically recognized by the controller and establish
the sensor range and gas code type.
Readout:
LED display exhibits the active channel
number and the corresponding sensor gas concentration
level. The display scans through all of the active channels
at 2-second intervals.
Warning and Alarm Set Points:
The Warning and Alarm
threshold levels are independently adjustable on the
controller and can be set to any value between 0 and
100% Full-Scale (FS).
Delay Function:
There are two user jumper selected
methods for setting the ZGARD C 4-Channel controller
warning and alarm delays. The first uses pre-
programmed, fixed delays of 5 minutes OFF delay for
warning and 5 minutes ON delay for alarm. The second
allows adjusting of the delays from 0 to 10 minutes using
potentiometers.
Warning and Alarm Scheme:
During a Warning event,
the associated Warning (Amber) LED will turn on and the
warning relay will be activated. No audible alarm is set off
at this time. Once a warning occurrence has been
abated, the associated warning LED will turn off and the
warning relay will be deactivated. If the 5 minute delay
feature is selected, then this action takes place after a 5
minute delay period.
During an Alarm event, the associated Alarm (Red) LED
will turn on and the alarm relay will be activated. If the 5
minute delay feature is selected and the alarm event has
prolonged for a period of 5 minutes, then the alarm relay
will be activated and the audible device will sound.
Pressing the reset button on the front panel will silence
the audible device. Once the alarm occurrence has been
abated, the audible device will silence (if not silenced
already by reset button) and the alarm relay will be
deactivated. If any other active channels reach the alarm
state, the audible device will sound with every new alarm
event. Once all of the active channels have been cleared
of alarm events, the audible device will silence (if not
silenced already by reset button) and the alarm relay will
be deactivated.
Sensor Fail:
If an analog sensor is used and the input is
between 1mA and 3.5mA, the Sensor OK LED will turn
off and the Sensor Fail Relay will be activated. Any
analog input below 1mA causes the controller to ignore
that analog input and treat that sensor as an RS485 type
sensor. If there is a lose of communication between the
controller and the remote gas sensor residing on the
RS485 network, the Sensor Fail Relay will be activated
and the Sensor OK LED will turn off.
Optional 4-20mA Output:
The analogue output
continuously represents the highest signal generated by
all of the active channel inputs.
4.0