Yokogawa UT55A / UT52A Mid-Level Digital Indicating Controller

A UTAdvanced controller with eight control modes for cascade and backup loops

The Yokogawa UT55A (96 x 96 mm) and UT52A (48 x 96 mm) sit above the UT35A and UT32A in the UTAdvanced range. Where the entry models are single-loop only, these controllers add eight selectable control modes: single loop, cascade primary, cascade secondary, cascade, loop control for backup, loop control with PV switching, loop control with PV auto-selector (maximum, minimum, average or difference) and control with PV hold. Cascade, backup and PV-switching modes need the remote auxiliary analog input, so choose a model code that includes it.

The control period can be set to 50, 100 or 200 ms (50 ms excludes cascade control and the Super functions), which suits fast pressure and flow loops as well as slow temperature loops. Feed-forward control is also available. The display is a 14-segment colour LCD whose PV colour changes on alarm, with a guide display showing parameter names, and the front is rated IP66 with NEMA 4 for the hose-down test only.

Technical specifications

Input and output capacity, ladder and networks

Input and output counts depend on the Type 2 code. For single-loop control on the UT55A, the table lists between one and four analog inputs, one analog output, up to nine contact inputs and up to eighteen contact outputs across the code range. A built-in ladder sequence function, a quick-setting mode that exposes only the minimum parameters, and LL50A parameter-setting software (sold separately) allow the logic and parameters to be built on a PC. Open networks are RS-485 (up to 38.4 kbps), Ethernet with serial gateway, CC-Link, PROFIBUS-DP and DeviceNet, the last three with a Modbus master function so one controller can poll other devices. The UT52A supports CC-Link and RS-485 only. Retransmission output or a 15 V DC loop power supply is standard.

Model code and options

The UT55A code is Type 1 (basic control: -0 standard, -1 position proportional, -2 heating/cooling), Type 2 (functions 0 to 7: for example 1 gives a remote analog input, six extra DIs, five extra DOs and RS-485; 4 gives a remote input and one extra DI; 6 gives 5 extra DIs and 15 extra DOs; 7 gives three auxiliary analog inputs and three DIs), Type 3 (open network 0 to 5), display language -1 to -4, case colour 0 white or 1 black and the fixed code -00. Options are /DR additional direct input (TC, 3- or 4-wire RTD) in place of the remote input, /LP 24 V DC loop supply, /HA heater break alarm, /DC 24 V AC/DC supply, /CT coating and /MDL DIN-rail mounting (GS 05P01C81-01EN). Footnotes restrict combinations (for example Type 2 codes 1 and 6 allow only Type 3 code 0), and /CT removes UL, CSA and CE conformity. The UT52A has a shorter Type 2 list (0 to 3) and the same Type 1 choices.

Installation and what to confirm before ordering

The case is 96 x 96 mm (UT55A) or 48 x 96 mm (UT52A) with 65 mm depth from the panel surface, wiring is by M3 screw terminals, supply is 100 to 240 V AC (18 VA for UT55A) and the operating temperature range is -10 to 50 C. Confirm which control mode you need and whether a remote setpoint or second process input is required, the sensor type, actuator output, alarm and contact I/O count, network, and panel size. The attached file is the Yokogawa general specification GS 05P01C31-01EN, which covers input accuracy tables, alarm types, communication physical layers and wiring diagrams. The related UT75A (96 x 96 with additional I/O) and the UT35A are in controllers and data acquisition. Send the complete code for a quotation.