MTL4850 Gateway Integration Manual

HMP-HM64 is equipped with four 20 way ribbon cable connectors (P1-P4) for receiving HART signals from HCU16, HCU16AO connection units, or backplates equipped with DIN41651 connectors. Each connector provides 16 signal connections and 4 grounding circuits to the module. The dedicated HM64RIB20 ribbon cable is used for this purpose, with standard lengths ranging from 0.5 meters to 6 meters. It should be noted that this cable is designed for internal connections within the cabinet and is not suitable for environments outside the cabinet.

In terms of address settings, HMP-HM64 is equipped with a five bit DIP switch array. Due to the interface accommodating two modules, the address setting adopts an even addressing method (0, 2, 4, 8, 16, 32). The address switch defines the address of module 1, and module 2 automatically uses its previous odd address. For example, if the address switch is set to 24 (switches 8 and 16 are turned on), module 1 uses address 24 and module 2 uses address 25.

In terms of power requirements, when both modules are installed, the current is 130mA @ 24V DC. Installation size: The weight of the carrier is 230g, and each module weighs 120g.

HCU16 and HCU16AO connection unit

The HCU16 HART connection unit provides a connection interface for on-site wiring and host/system control for safe area applications, as well as a point for accessing HART signals for maintenance systems. Each channel has three terminals: positive, negative, and transmitter power supply terminal (Tx+). Similar to HTP-SC32, HART signals must be terminated with an impedance of approximately 240 Ω, and installation positions for parallel or series resistors are reserved on the circuit board.

This unit can be used for analog output, provided that the system's current signal is compatible with HART communication. The on-site signal and system connections are completed through screw terminals. Installation size: The weight of the carrier is 330g, and the height from the top of the DIN rail is 53mm.

HCU16AO is a variant product specifically designed for analog output applications. Many systems' 4-20mA analog outputs are not compatible with HART data due to their typically low impedance. In addition, noise generated by analog output can sometimes interfere with HART data, or vice versa affect the stability of current signals. HCU16AO solves this problem in non hazardous areas by having 16 isolated channels, each of which is connected in series with a low-pass filter in the system current signal path. This filter has almost no effect on 4-20mA signals, but provides a suitable high impedance (>240 Ω) for the detection and measurement of HART signals. The on-site and system connections are achieved through pluggable eight position screw terminals, divided into four groups according to four channels per group. The weight of the unit carrier is 770g, and the height from the top of the DIN rail to the top of the screw connector is 58mm.

Integrated scheme of isolator based on CPH backplane

For application scenarios that require intrinsic safety isolation, MTL offers CPH-SC16 (R) and CPH-SC32 (R) series backboards. These backplanes are designed for the MTL4500 series analog input and output modules, with each backplane capable of accommodating 16 MTL4500 modules and one MTL4850 HART multiplexer module.

The CPH-SC16 and CPH-SC16R backboards support 16 HART channels, but by connecting a second CPH-SC16 (or 16R) backboard, the MTL4850's 32 channel capacity can be fully utilized. They are mainly designed for MTL4541, MTL4541A analog input module, and MTL4546 analog output module. The CPH-SC16R version has a 250 Ω resistor connected in parallel at both ends of the control system terminals, providing 1-5V signals to the host - this version can only use MTL4541 and MTL4541A modules.

The P1 and P2 connectors equipped at both ends of the backplane are used to connect a pair of CPH-SC16 (or 16R) backboards. When using this connection method, only the backplane with MTL4850 installed (carrying modules 1-16) needs to be connected to the RS485 serial link.

The CPH-SC32 and CPH-SC32R backboards support 32 HART channels and are mainly designed for MTL4544, MTL4544A analog input modules, as well as MTL4549, MTL4549C analog output modules. The CPH-SC32R version also has 250 Ω resistors connected in parallel at both ends of the control system terminals, and can only use the MTL4544 module.

All CPH backboards are equipped with two RS485 ports for connecting to maintenance PCs and cascading downstream to other backboards or HART interfaces. If a pair of backplane connections are used, the RS485 serial link should only be connected to the backplane where MTL4850 is installed.

In terms of power supply, the backplane provides dual redundant 24V DC power supply through independent four screw terminal connectors. Each redundant power input is equipped with LED indicator lights. The series diode at the input prevents mutual interference between two power sources, and the 0.5A fuse provides overcurrent protection. Power requirements: Voltage 20-35V DC, current consumption on CPH-SC16 (R) maximum 0.65A @ 24V DC (all channels 20mA), and maximum 1.2A @ 24V DC on CPH-SC32 (R).