4
NOTE: The HC-220 can power the 4-20mA source via 24VDC for both the PV1 and PV2 inputs (e.g.
loop powered input). This will change how these inputs are connected. Refer to Figure 3 for additional
details.
PV1(Flow)
AI1/V- = Source powered 4-20mA input.
AI1/V+ = Loop powered 4-20mA input.
PV2
(Residual)
AI2/V- = Source powered 4-20mA input.
AI2/V+ = Loop powered 4-20mA input.
6.
Electrical Outputs
– The following outputs are available:
a. The HC-220 includes two (2) SPDT alarm relays. Each relay can be independently selected as either
representing normal alarms or whether the HC-220 is in AUTO or Manual mode.
b. 4-20mA Output – The HC-220 is equipped with two (2) 4-20mA outputs which are used to control
chemical feed rate.
7.
RS-485 Modbus Communication
– This feature allows the HC-220 to be monitored and controlled by a
computer. See Hydro Instruments’ Modbus Communication Setup document for further details.
II. CONTROL FEATURES
1.
Keypad Operation
– The keypad is used in all three modes of the HC-220. Generally the keys are used
as outlined here below. However, detailed instructions will follow.
a. &
keys – These keys are used to cycle through the various display screens. These keys will be
referred to as “up arrow” and “down arrow”.
b. &
keys – These keys are generally used to adjust settings and values within the screen being
displayed. These keys will be referred to as “plus” and “minus”.
2.
Dip Switches
– These switches are used to select whether the analog input channels are to be used for
0-10 Volts or 4-20mA.
a. Switches 1 and 2 on the MB124 circuit board are used for the PV1 (Flow) input channel.
4-20mA: 1 = On, 2 = Off
0-10V: 1 = Off, 2 = On
b. Switches 3 and 4 on the MB124 circuit board are used for the PV2 (Residual) input channel.
4-20mA: 3 = On, 4 = Off
0-10V: 3 = Off, 4 = On
